Testing device for telephone-exchange systems



April 13 1926.

w. P. ALBERT TESTING DEVICE FOR TELEPHONE EXCHANGE svs'rsms Filed May 11, 1923 4 Sheets-Sheet 1 Sal i mi TR T8 a o o one o o 0 Wa/fer A A/ken.

April 13 {1926.- 15803 W. P. ALBERT TESTING DEVICE FOR'TELEPHONE EXCHANGE SYSTEMS Filed May 11, 1923 4 Sbeets-$heet 2 April 13 1926 W. 'P. ALBERT TESTING nsvxcz FOR TELEPHONE sxcnmensyswms Filed May 11 1923 4 Sheets-Sheet 5 Mvea/or:

Wd/fer EA/be/"If April 13 1926. w. P. ALBE-RT TESTING DEVICE FOR TELEPHONE EXCHANGE SYSTEMS Filed y 11, 1925 Q Patented Apr. 13, 1926.

UNITE STATES PATENT OFFICE.-

VVALTER P. ALBERT, OF EAST ORANGE, NEW JERSEY, ASSIGNOR T0 WESTERN ELEC- TEIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION.OF NEW YORK.

TESTING DEVICE FOR TELEPHONE-EXCHANGE SYSTEMS.

I Application filed May 11, 1923. Serial No. 638,217i

To 0Z3 "whom. it may concern:

Be it known that I, VJALTER P. ALBERT, a citizen of the United States of America, residing at East Orange, in the county of Essexand State of llew Jersey, have invented certain new and useful Improvements in Testing Devices for Telephone-EXchange Systems, of which the following is a full, clear, concise, and exact description.

This invention relates to a telephone exchange system and more particularly to a testing device for locating faulty selector switches employed in machine switching systems. 7

One of the principal requirements in the operation of the telephone exchange system operating either on a manual Or mechanical basis is that of maintaining the central office equipment in proper working condition. In the case of manual exchanges the central oiiice equipment is relatively simple and the problem of keeping such apparatus in good working order is a comparatively one. However, in the case of mechanical oilices the central office equipment is much more complicated and the establishment of different classes of calls brings into operation, in varying combinations, selector mechanisms of various types, each of which affords opportunities for trouble to arise. The amonnt'ofapparatus used in'mechanical exchange systems is very large and much of it is made up of moving parts subject to loss of adjustment. Allapparatus of this nature, such as relays,interrupters. sequence switches, clutches and selector mechanisms must be watched to detect wear, or broken parts or loss of adjustment which may be a result of normal use of the equipment, or the result of mistreatment. Naturally, the failure of any piece of apparatus to function properly will result .in the stopping of the progress of calls.

Such failures ordinarily would not be detected except where calls are repeatedly reported as incomplete, and such service interruptions, if frequent enough, would assume serious proportions from a service standpoint. A fault in a selector switch, causing it to be deterred in its progression when a call is partly completed, will often operative relationship cause other apparatus connected to it to remain in an off-normal position. It is highly desirable in tracing troubles of this nature to determine which selectors are connected in cooperative relationship. By this method the position of the sequence switches of the cooperating selector switches can be noted and in the majority of cases the offending element may be quickly discerned and eliminated so that the selector switches can be again placed in service, thus reducing the cost of operation and maintenance of a telephone exchange of this type.

It the object of this invention to provide a testing device for enabling tests tobe made to locate selector switches connected in col on non-completed service connections. More'particularly it is the object of this invention to provide a testing device, to determine which district selector switch. is connected in cooperative relationship, with a sender, thathas been arrested in its progression.

While the invention has been disclosed as particularly adapted for testing switches of the panel type, it will be however, apparent from the following description that the invention has a wider utility and that, by

slight modification, it could be adapted for testing other types of switches.

A feature of the invention relates to the provisionof means for locating one of a plurality of district selector switches known to be connected to a sender that has been arrested in. its progression.

v A further feature of the invention relates to the provision of means to indicate which dlstrlct selector is connected iii-cooperative relationship with a sender selector that has" been-indicated as in trouble.

A further feature of this testing device is in its ability to detect unstandard conditions in aplurality of selector switches at one time with signaling means to indicate the location of the selectors in trouble.

These and other features of the invention will be apparent from the following de scription taken in connection with the accompanying drawings. Figs. 1, 2 and 8 show portions ofapparatus employed in cs tablishing connections and Fig. 4. the test' ing device upon which this invention is based. These drawings should be a ranged for consideration in accordance with the diagram'of Fig. 5.

Fig. 1 shows a district selector of the type completely disclosed in the patent to A. E. Lundell, No. 1,550,377, issued Aug 18, 1925.

Fig. 2 shows a timing device. operable from the sender selector switchto indicate after a predeterminedtime that a sender has remained in a given position longer than necessary to complete its service connect-ion.

Fig. 5.) shows diagran'iniatica-lly such portions of sender as are necessary to an under standing of this invention. A complete sender of this type is disclosed in the patent to A. E. Lundell, hereinbefore referred to.

Fig. 4 shows the testing device. The portion above the dotted line illustrates the mechanism for locating a district that is connected to a sender, that has given a signal indicative that its progression has been arrested. This portion of the testing circuit shows apparatus for a group of 300 dis.

tricts. There may be several of such groups in an otlice and therefore the same number of groups of the apparatus shown to theleft of the dotted line will be required as there are roups of districts. The apparatus shown below the dotted line is co-mmonto any number of such groups.

Description of apparatus.

The keys shown in Fig. 4 numbered 493,

494 and 495 are of the non-locking type.

General description of utility and operation.

In one type of machine switching system the subseribeids line terminates a line switch responsive to the switehhool: of the subscribefs set. The line switch in turnselccts an idle district switch which through an associated sender selector becomes connected with an idle sender of the register type. The sender registers. are responsive to the impulses transmitted from the dial at the subscribers station translating these pulses in such a manner that other selector switches are directed to select the called line.

.If these selections are only partially completed due to an unstanda'rd condition in one of the selector switches, the progressive functioning of the $ender will be arrested and after a predetermined period of time the sender monitor lamp is lighted to indicate this condition. I

The district selector switches are divided into large groups and the senders into oomparatively small groups. It is therefore readily seen that when an unstandard condition isencountered, when partialw selection has taken place, that without the provision of'special testing equipment it is ditlcult to determine which district selector is connected tothe sender that has given a signal showing incomplete selections. The testing circuit of this invention has therefore been (.lGVGlOPGCl for use in combination with the ard conditions exist. This unstandard condition may exist in either the district selector, associated sender or from apparatus connected thereto as well known in the art.

lVhen a district connected to a sender flashing a trouble si nal is found by one of the switches of the testing device, the apparatus of the testing device is operated in such manner that one of lamps 488 to 492, inclusive, will be lighted. These lamps indicate in which group of twenty the particular district which is engaged in a deterred connection is located. Also a lamp connected through brush 416, 436, 456, etc., will be lighted to indicate the particular district in a group of twenty and one of lamps 422, 424, 426, etc, will he lighted to indicate the group of one hundred in which the district is located. Thiscombination of lamps will indicate to the test man the exact location of the district selector that is connected to a combination of selectors in which anunstandard condition exists.

' Step-by-step switches of a well known type are used in this invention and the combination is such that a plurality of district selectors are tested upon each step of the switch in this testing device. I

This testing device may be used to find unstandard conditions in several district selectors at one time, i. e., the testing device may hunt for a district inan unstandard condition and when that is found the testing circuit may again be advanced to hunt for another district in an unstandard condition. More than. one district in an unstandard condition may be found when one of the step-by-step testing switches is resting in a i g p i n. This would be indicated by more than one of lamps 488, 489, 4:90, 191 or s92 being lighted at the same time.

It will be noted that only three of the lamps representing the number within the twenties have been shown connected to the terminals of switches 410, 4:80, 450, etc, there are, however, twenty lamps connected to the terminals of these switches, the first, ninth and twentieth being shown.

Detailed description.

Since the functioning of the district selector, Fig. 1 and sender Figs. 2 and 8 in theestablishment of regular service connections enters only incidentally into the consideration of this invention reference to the patent of A. E. Lundell, hereinbefore re' ferred to is made for a complete description thereof. This description will, therefore, only cover the operation from a point where a sender and district become arrested in their progression due to trouble from one of various causes known in the art. Selector switches arrested in their progress1on on account of trouble will be known in this disclosure as unstandard selector switches.

When a sender is taken for use in establishing a connection, a circuit is established for operating the time measuring device shown in Fig. 2 which may be traced from ground through the'upper contact of sequence switch spring 311 (FA-P18) cond'uc- 311 over the circuit previously traced, also an operating circuit for relay 222 which is effective when interrupter 225 rotates to nterpose an insulated segment in; the circuit. The operation of relay 222 establishes a path for operating-relay 221. This path, however, is not effective until interrupter 225 has rotated to engage a conducting segment with its brush. The path for operating relay 221 may be traced from ground, through the upper contact of sequence switch spring 311 (1 +18) outer left contacts of relay 250, contacts of relay 223, winding of relay 221, alternate contacts of relay 222, outer right normal contacts of relay 226, conducting segment of interrupter 225, left normal contacts of relay 226, winding of relay 228, to grounded battery. Relay 221 in attracting its right contacts esablishes a circuit for operating relay 226 which may be traced from grounded battery through the winding of relay 226, right inner normal contacts of relays 285, right contacts of relay 221, outer left normal contacts of relay 250, upper con tact of sequence switch spring 311 (1 /1;|-18) to ground. tablishes locking path for itself traced from grounded batterythrough the winding of relay 223, left contacts of relay 221, right tact-s, establishes a circuit for operating switch magnet 22? when interrupter 225 enconducting segment with its brush. This circuit may be traced from ground connected to terminals of switch bank 260, brush 228, outer right alternate contacts of relay 226, interrupter 225, left alternate contacts of relay 226, left outer normal contacts of relay 235, winding of switch magnet 227 to battery. When interrupter 225 rotates to en gage its brush with aninsulated segment, magnet 22? will release thus causing the switch 27 5 controlled thereby to advance one step. 7 As the interrupter 225 continues to rotate, switch 250 will be caused to step from terminal to terminal.

Relay 226 in closing its left alter- At its left contacts relay 221. es-

Since the amount of time for the switch 1 During selections, with sequence switch spring 304: in positions 3+15, a circuit is established for operating relay 310 which may be traced from grounded battery through the windingof relay 310, contacts I of sequence switch spring 304 (EH-15) nor anal contactsof relay 305, normal contacts of relay 303, to ground. Relay 310 looks over a path (not shown) and in closing its outer left contacts connects ground to con ductor 1-11 in Fig. 1 over a circuit which may be traced from ground through the outer left contacts of relay310, left normal contacts of relay 309, left normal contacts of relay 308, conductor 1447., switch wipe-r 1.43, lower contacts of sequence switch spring 142 (3+10) outer right alternate contacts of. relay 121, to conductor 141. A branch of this circuit extends over conductor 4-45 to a bank terminal of testing switch 100. Similarly a conductor is connected from the terminal banks of the testin device Fig. 1, to each district selector switch.

Lamp 219, associated with each sender,

will'indicate the particular sender that has ship with the testing device until a district been deterred in its progression, and since this sender is one of a group common to a given group or" district .selectors, the test man will know the group of district selectors in which to hunt for the district that is associated with such sender.

Key 493 is used to start the testing circuit hunting for a district in one group or" one. hundred districts and keys 494 and 495 are used as start keys for hunting a district in other groups of districts. Two of these ke s cannot, however, be used simultaneously. The description will be confined to the apparatus associated with key 493. p

The test man noting the flashing of lamp 219, actuates and releases key 493. The actuation of this key establishes a path for operating relay 499 which may be traced from grounded battery, through the wind ing of relay 499, lower contacts of key 493, to ground. This relay functions to release any of relays 483 to 487 inclusive that may have been operated from a previous test as will be described hereinafter. The upper contacts of key 493 establish a circuit for operating relay 406, which may be traced from grounded battery, through the winding of relay 406, upper contacts of key 493, inner lower, normal contacts of relay 407-, lower normal contacts of relay 408, contacts of relay 480, to ground. The outer lower contacts of relay 406 are not effective at this time. The lower inside contacts of relay 406 establish a locking circuit for itself to the ground at the contacts of relay 480 as traced. This relay also establishes a circuit for lighting lamp 422, traced from grounded battery through resistance 423, lamp 422, contacts of relay 406, thence as previously traced through contacts of relay 480, to ground. At the upper inside contacts of relay 406 a path is established for operating relay 403 which may be traced from grounded battery, through thewinding of relay 403, contacts of switch magnet 400, contacts of relay 406, lower normal contacts oit key 495, lower normal contacts of key 494, lower normal contacts of key 493 to ground as soonas key .493 is released. The upper outside contacts of relay 406 are ineffective at this time. The operation otrelay 403 establishes an obvious circuit for operating switch magnet 400.

The operation of switch magnet 400 opens the operating circuit for relay 403 which releases, in turn releasing switch magnet 400' and causing the switch to step one terminal in the manner well knownin the art. Switch magnet 400-. upon releasing, reestablishes the operating circuit for relay 403, which again reestablishes the operating circuit for switch magnet 400. In this manner magnet 400 in termittently energizes I and advances the switch brushes step by step, at each step bringing districts into operative relationis located having a ground connected to lead 141 as hereinbefore described.

Assuming that the district in which the trouble exists, is connected to conductor 445, switch 400 will be rotated approximately half of the arc, Where it will stop due to the completion of a circuit for operating relay 484. This circuit may be traced from ground, through the outer contacts of relay 310, contacts of relay 309, contacts of relay 308, conductor 144, brush 143, lower contacts'of sequence switch spring 142' (3-l-10) right outer alternate contacts of relay 121, conductor 445, terminal of switch bank 412, brush 418, contacts of relay 499, winding of relay 484, to grounded battery. Relay 484 in closing its lower inside contacts, establishes a circuit for lighting lamps 4'89 and 467 which may be traced from grounded battery through lamp 467, terminal 11 of switch bank 410, brush 416, lamp 489, upper contacts'of relay 484, lower normal contacts of key 495, lower normalcontacts of key 494, lower normal contacts of key 493, to ground. Relay 403 being slow to release, a circuit is established for holding it in an operated position. throi' gh the lowermost contactsof relay 484. This circuit may be traced from grounded battery, through the winding of relay'403, upper outside contacts of relay 406, lower most contacts of relay 484', lower normal contacts o't keys 495, 494 and 493, to ground. Relay. 403 is now held in an operated position thus maintaining a circuit for holding switch magnet 400 in an operated position, to prevent the switch fromstepping fur ther, until the circuit for holding relay 403, has been opened by the operation of key 493.

Lamp 422, which has remained lighted, indicates'to the test man that the district is one of the first hundred. Lamp 489, indicates that the district is connected to the terminals of. switch bank 412, and is therefore in the second, twenty oi the first hundred, and lamp 467 indicates that the district connected is in the second twenty. Therefore, by the lighting or these three lamps, the fact is established that the district in trouble is the 29th district, in the first one hundred districts, in the group of districts under test. Should the complete rotation of switch 400 not locate a district in trouble this switch would be stopped on terminal No. 1

by ground connected to conductor 446 over a circuit which may be traced from ground, through the lower normal contacts of key 493, lower normal contacts of key 494, lower normal contacts of key 495, conductor 446, brush 417, contacts of relay 499, winding of relay 483, to grounded battery, operating relay 483. Relay 483 in attracting its lower contacts establishes a circuit for holding relay403 in an operated position,

which path may be traced from grounded battery, through the winding of relay 403, upper outside contacts of relay 406, contacts of relay 488, lower normal contacts of keys 495, 494 and 498, to ground. Relay 403 is held in an operated position and in turn holds switch magnet 400 in an operated position to prevent further stepping of the switch. lVith switch 400 resting on terminal No. 1 a circuit is established for operating relay 482 which may be traced from ground ed battery, through the winding otrelay 482, terminal No. 1 of switch bank 410, brush 416, lamp 488, lower inside contacts of relay 488, lower normal contacts of keys 495, 494 and 493, to ground. The operation of relay 482 establishes a circuit for operating relay 407, which may be traced from grounded battery, through the winding oil relay 407, lower outside contacts of relay 406, contacts of relay 482, to ground. Relay 407 in closing its lower inside contacts opens the holding path for relay 406 which re leases. The release of relay 403 will in turn release relay 403 which in turn releases switch magnet 400, causing the switch to advance one terminal bringing it to rest at its normal position. The release of relay 406 also opens the circuit for lamp causing it to be extinguished. lhe stepping of the switch to normal releases relay 483. Relay 407 in closing its lower inside contacts establishes a locking ircuit .i'or itself which may be traced from grounded battery through the winding of relay 407,;low: er inside contacts of relay 407, lower normal contacts of relay 408, contacts of relay 480, to ground. The closure oi the same contacts establishes a circuit for lighting. lamp 424 which may be traced from the locking ground of relay 407, through lamp 424 ,'rcsistance 425, to grounded battery. The upper inside contacts of relay 407 establish a circuit for operating relay 404, which may be traced from grounded battery, through the winding of relay 404, contacts of switch magnet 401, upper inside contacts of relay 407, lower normal contacts oi keys 494 and 493, to ground. The upper outside contacts of relay 407 are not ellectivc at this time. Relay 404 in attracting its contacts establishes an obvious circuit for operating switch magnet 401. The actuation of switch magnet 401 opens the operating circuit for relay 404 causing it to release which in turn opens the operating circuit l'or switch magnet 401 causing the switch to advance one step from normal to the first districts of the live groups 01"- twenty in the second hundred of the district group.

Switch magnet 401 upon releasing, re-

establishcs the operating circuit for relay 404 which in turn recstablishes the operatlng circuit for switch magnct 401, which upon operating a-gam opens the operating the group.

establishes a circuit for operating relay 481.

circuit for relay 404, releasing it and in turn again releasing switch magnet40l causing the switch to take a second step to connect the testing circuit with other districts in This switch thereupon continues to step from terminal to terminal in the above described manner until it has found a district in trouble when it will stop in the manner hereinbefore described and light certain of the lamps to show the location of the district selector in the combination of selector switchesin which an unstandard condition exists. If an unstandard condition is not located in the second hundred, the switch will rotate to the terminal connected to condoctor 447 where it will stop in the manner described for switch 400.

Brush 437 connected to conductor447 establishes a circuit for operating relay 483, which may be traced from grounded battery, through the winding of relay 483, contacts of relay 499, brush 437, conduct-or 447, l0wor normal contacts of keys 495,494 and 498, to ground. The operation of relay 488 estab lishes a holding circuit for relay 404 which maybe traced from grounded battery, through the winding of relay 404, upper outside contacts of relay 407, lower contacts of relay 488, lowernormal contacts of keys 494 and 498, to ground. The establisht' of this holding circuit for relay 404 l in turn hold switch magnet 401 in an ping of the switch to the next terminal. Relay 488 in closing its lower inside contacts which may be traced from grounded battery through the winding of relay 481, terminal 1, of switch bank 480, brush 436, lamp 488, inside contacts ct relay 483, lower normal contacts of keys 495, 494 and 493, to ground. Relay 481 in closing its contacts establishes a circuit for operating relay 408 which may be traced iroi'n grounded battery, through the winding of relay 408, lower outside con tacts of relay 407, contacts of relay 481, to

.nd. Relay 408m attracting its lowerconta-c ,7: opens the holding circuit of relay 407 causing its rclease,which in turn causes'the rel ass of relay 404, opening the energizing circuit of switch magnet 401 and in turn causing the switch controlled by this switch magnet to advance one step bringing its ln'usli'es to rest on the normal terminals oi that switch. This switch, in stepping/to normal, releases relay 483. The release of relay 407 also extinguishes lamp 424.

Relay-408 in closing its lower contacts establishes a locking path for itself which may be traced "from grounded battery, through the winding of relay 408, lower contacts of relay 408, contacts of relay 480, to

ground. Relay 408 in attracting its upper contacts establishes a circuit for operating the district group in a selector switch combination in which an unstandard condition exists. Should a faulty SGlQCtOI SWItCh be encountered when the switch is rotating over:

the leads connected to said districts, the switch would be arrested in its progression in the manner previously described for the district located in the first districts tested. If, however, no faulty selector switch is discovered during the rotation of this switch, it will come to the rest on terminal 1 bringing brush 457 into connection with conductor 448 establishing an operating circuit forv relay 483, which may be traced from grounded battery, through the winding of relay 483, contacts of relay 499, brush 457, conductor 448, lower normal contacts of keys 495, 494 and 493, to ground. Relay 483 in attracting its 'lower out-side contacts establishes a holding path for rela'y 405 which may be traced from grounded battery, through the winding of relay405, upper outside contacts of relay 408,'lower contacts ofrelay 483, lower normal contacts of keys 495, 494 and 493, to ground thus preventing the switch controlled by switch magnet 402from stepping further at this time. p,

With this switch brushes resting on terminal 1, a circuit is established for the op eration of relay 480 which may be traced from grounded battery, through the winding of relay 480, terminal No. 1 of switch bank 450, brush 456, lamp 488, lower inside contacts of relay'483, lower normal con tacts of keys 495, 494 and. 493, to ground. The operation of relay 480 opens the looking circuit for relay 408 causing its release and extinguishing of lamp 426. The release of relay 408 in turn causes the release of relay 405 and the release of switch magnet 402 causing it to advance the switch one step into its normal position. The switch in stepping from terminal 1 to its normal position opens the operatingl circuits for relays 483 and 480 which release.

The testing circuit shown on Fig. 4 now has all of its apparatus in a normal nonoperated condition and may again be used for locating faulty selector switch circuits by the depression of one of the start keys 493, 494 or 495.

\Vhen the district has been located that is connected to a sender giving the trouble signal, an investigation is made to determine the nature of the trouble. If the district is found to be in standard condition the succeeding selector switches, which are em ployed in the established connection, over the brushes154, 157 and 146 of the district and conductors 704,159 and 720 may be located and tested. An unstandard condition in any of the selector switches, to which conductors 704, 159 and 720 are extended, would cause the sender Fig. 3, to be deterred in its progression, the same as would an unstandard condition in the district or sender Figs. 1 and 3, respectively.

The patent of Alben E. Lundell, No. 1,550,377, issued Aug. 18, 1925, has been referred to as a basis for portions of this disclosure. To aid in the facility of applying this reference, the numbering of the apparatus for Fig. 1 is the same .as that shown in Fig. 2 of the above patent. The apparatus shown in Fig. 3 has been given two sets of numerals. The numerals that are not shown in brackets have been used in this disclosure, and the numerals shown in brackets are those that are shown in the disclosure of the sender in the above mentioned patent.

' lVhat is claimed is:

1. In a telephone exchange system, a plurality of selector switches, a sender commonly available to said selector switches, means to associate said senders with one of said selector switches, means to cause said sender to functionin a progressive manner to control selector switches, a testing device associated with said selector switches, and means to operate said testing device to locate a selector switch associated with an improperly functioning sender.

2. In a telephone exchange. system, plurality ofselector switches, a sender commonly available to said selector switches, means to associate said sender with, one of said selector switches, means to cause said sender to function in a progressive manner to control selector switches, a testing device associated with said selector switches, means to operate said testing device to locate a selector switch associated with an improperly functioning sender, and signaling means to indicate the location of the selector switch associated with said improperly funcprogression of said sender, a testing device associated with said selector switches, and means to operate said testing device to locate said unstandard selector;

4. In a telephone exchange system, a pinrality of selector switches any of which may be in an unstandard condition, a sender com- Lil monly available to said selector switches, means to associate. said sender with one of said selector switches, means to cause said sender to function in a progresive manner to control said selector switches said sender being arrested in its progressive operation when associated with an unstandard selector, signaling means responsive to said arrested progression 0t said sender, a testing device associated with said selector switches, means to operate said testing device to locate said unstandard selector, and signaling means to indicate the location of the selector switch in which the unstandard condition exists."

5. In a telephone exchange system, a plurality or selector switches, a testing device, means for associating a plurality of said selector switches in operative relation with said testing device at one time, each switch being individually.connected to said testing device, and signaling means to indicate simultaneously that certain of said selector switches thus associated are in an unstand ard condition.

6. In atelephone exchange system, a plurality of selector switches, a testing device, means for associating a plurality of said selector switches in operative relation with said testing device at one time, each switch being individually connected to said testing device, and signaling means to simultaneously indicate the location of any of said selector switches thus associated inwhich an unstandard condition exists.

7. In a telephone exchange system, a plu rality of selector switches, a testing device, means whereby said plurality of selector switches may be associated in operative relation with said testing device successively in small groups, each switch being individually connected to said testing device, and signaling means to indicate the location of any of said selector switches in which an unstandard. condition exists.

8. In a telephone exchange system, a plurality of like combinations of varied selector switches, a testing device, means whereby said plurality of combinations of selector switches may be associated in operative relation with said testing device successively in small groups, each combination being individually connected to said testing device, and signaling means .to indicate the location of any of said combination of selector switches in which an unstandard condition exists.

9. In av telephone exchange system, a plurality of selector switches, a testing device,

means to operate said testing device for making routine test of said switches, means whereby said plurality of selector switches may be associated in operative. relation with said testing device successively in small groups, each switch being individually connected to said testing device, and means to nation being individually connected to said. testing device, and means to arrest said test-- ing device when an unstandard selector is thus associated with'said testing device or in its starting position if no unstandard selector is associated therewith.

11. In a telephone exchange system, a plurality of selector switches, a testing device, means whereby said plurality of selector switches may be associated in operative relation with said testing device successively in small groups, each switch being individually connected to said testing device, certain of said selector switches being in an unstandard condition, means to arrest said testing device when one or more unstandard selector switches of one of said groups are thus associatedwith said testing device, and signaling means to indicate the location of each unstandard selector switch.

12. In a telephone exchange system, a plurality of combinations of selector switches, a testing device, means whereby said plurality of combinations of selector switches may be associated in operative relation with said testing device successively in small groups, each combination being individually connected to said testing device, means to arrest said testing device when one or more unstandard selector switches is associated with said testing device, and signaling means to indicate the'location of each unstandard selector switch.

13. In a telephone exchange system, a plurality of selector switches, a sender com- ,monly available to said selector switches,

means to associate said sender with one of i said selector switches, other selector switches,

ly available to said selector switches, means to associate said senders with said selector switches. other selector switches connected in cooperative relation with said first named switches, means to cause said senders to function in a progressive manner to control said switches, said sendersor switches being arrested in their progressive operation when unstandard, a testing device, means whereby said first named selective switches may be associated in operative relation with said testing device successively in small groups, and means to arrest said testing device when associated in operative relation with switches in which an unstandard condition exists.

15. In a telephone exchange system, a plurality of selector switches, senders commonly available to said selector switches, means to associate said senders with said selector switches, other selector switches connected in cooperative relation with said first named selector switches, means to cause said senders to function in a progressive manner to control said switches, said senders or switches being arrested in their progressive operation when unstandard, a testing device, means whereby said first named selector switches may be associated in operative relation with said testing device successively in small groups, and signaling means to indicate the location of selector switches that are in an unstandard condition.

16. In an electrical testing system, sets of fixed terminals, a plurality of electrical 'devices connected to said terminals, brushes, means for advancing said brushes over said terminals, means for arresting said brushes when terminals are encountered to which unstandard devices are connected, and signaling means to denote the location of several of said electrical devices in an unstandard condition in any single position of said brushes.

17. In an electrical testing system, a plurality of electrical devices to be tested, divided into a plurality of groups and .subgroups, a testing device comprising a plurality of hunting switches, one for each group of devices, a plurality of banks of terminals for each of said switches, means for connecting a group of devices by sub-groups to the terminals of the several banks of the respective switch, means for operating said switches in succession to hunt for devices which are in an unstandard condition, means for arresting any of said switches when an electrical device is found to be in an unstandard condition and indicating means associated with the several banks ofeach of said switches and with the arresting positions of each Switch for indicating the groups, sub-groups and particular device in the sub-group in which the unstandard condition exists.

18. A plurality of lines arranged in groups, a switch, a contact bank, for said switch in which said lines terminate, a plurality of brushes for said switch, ieans to advance said brushes over said contact bank, indicating means associated with certain ones of said brushes to indicate the group locations of a plurality of lines and other indicating means associated with one of said brushes to indicate the locations of said lines within their respective groups.

In witness whereof, I hereunto subscribe my name this 10th day of May A. D., 1923.

WALTER P. ALBERT. 

